The cervical spine is the most mobile part of your spine. It consists of seven vertebrae (C1 to C7) that support your head and allow for a remarkable range of motion. Understanding this anatomy helps you demystify neck pain and realize why your neck is much stronger than you think.

Your neck performs a remarkable feat every day. It supports the weight of your head (approximately 5 kg) while allowing you to turn, tilt, and bend in all directions. This combination of stability and mobility makes the cervical region a truly unique structure in the human body.

What makes the cervical spine unique compared to the rest of the spine?

The cervical spine differs from other regions of the spine in its exceptional mobility, smaller vertebrae, and the presence of special holes in the vertebrae for the vertebral arteries. These characteristics allow for head movement while protecting vital structures such as the spinal cord.

Unlike the thoracic vertebrae (attached to the ribs) or lumbar vertebrae (which are more massive to support weight), the cervical vertebrae are smaller. Their reduced size can be explained by a simple reason: they support less weight than the vertebrae in the lower back. However, this small size does not mean they are fragile. Your cervical vertebrae are remarkably robust and well suited to their function.

The typical cervical vertebrae (C3 to C6) share unique characteristics:

| Feature | Description | Function |

|-----------------|-------------|----------|

| Small vertebral body | Smaller than thoracic and lumbar vertebrae | Adapted to the reduced load of the neck |

| Triangular foramen | Triangular opening for the spinal cord | Protection of the spinal cord with adequate space |

| Bifid spinous process | Split tip | Muscle attachment points |

| Transverse foramina | Holes in the lateral processes | Passage of the vertebral arteries |

To understand how the cervical region fits into the overall spine, see our guide to the anatomy of the spine.

How are the seven cervical vertebrae organized?

The seven cervical vertebrae are divided into two distinct functional regions. The first two vertebrae (C1 and C2) form the upper cervical region and have unique shapes. The other five (C3 to C7) form the lower cervical region and share a more typical structure.

What makes C1 (the atlas) so special?

The atlas (C1) is the first cervical vertebra. Unlike other vertebrae, it has no vertebral body or spinous process. It forms a bony ring that directly supports the skull. Its name comes from the Titan Atlas in Greek mythology, who carried the world on his shoulders.

The atlas has a unique structure:

• Ring shape: Unlike other vertebrae, C1 is essentially a ring of bone.
• Lateral masses: Two bony masses on each side that articulate with the skull and C2.
• No vertebral body: The "body" of C1 has fused with C2 to form the dens.
• Anterior and posterior arches: Connect the lateral masses into a complete ring.

The joint between the skull and C1 (atlanto-occipital joint) mainly allows for "yes" movements—flexion and extension of the head. Approximately 50% of the flexion-extension of your neck occurs at this joint alone.

What is the role of C2 (the axis)?

The axis (C2) is the second cervical vertebra. It has a unique bony projection called the dens (or odontoid process) that rises from its vertebral body. This projection acts as a pivot around which C1 rotates, allowing the head to move.

The dens is the distinctive feature of C2. It is a tooth-shaped projection that rises upward, articulating with the anterior arch of C1. This configuration creates a pivot-type joint, allowing your head to turn from left to right.

Remarkably, approximately 50% of your neck's rotation occurs at the joint between C1 and C2 (atlantoaxial). When you turn your head to say "no," it is mainly this joint that is working.

What distinguishes C7 from other cervical vertebrae?

C7, also known as the prominent vertebra, has a longer, non-bifid spinous process that you can easily feel at the base of your neck. This vertebra marks the transition between the cervical and thoracic regions of the spine.

When you tilt your head forward and touch the base of your neck, the bony bump you feel is likely C7. This is a useful anatomical landmark for healthcare professionals. C7 is also unique because the vertebral artery typically passes around this vertebra rather than through its transverse foramen.

How do cervical intervertebral discs function?

Cervical discs act as cushions between the vertebrae. They are thicker at the front than at the back, which contributes to the natural curvature of the neck. They allow flexibility while absorbing shock during everyday movements.

In the cervical region, the discs account for approximately 40% of the total height of the cervical spine—a higher proportion than in other regions of the spine. This increased proportion contributes to the neck's exceptional mobility.

Each cervical disc is composed of two parts:

• Nucleus pulposus: The gelatinous center that absorbs shocks. In young people, it contains a lot of water. After age 30, it gradually becomes more fibrous.
• Fibrous ring (annulus fibrosus): The outer layers of collagen that contain the nucleus.

A distinctive feature of cervical discs: the unciform processes (small bony projections on the lateral edges of the cervical vertebrae) limit excessive lateral movement of the discs. This protection explains why lateral cervical disc herniations are less common than in the lumbar region.

If you want to learn more about herniated discs in the cervical spine, check out our comprehensive guide to cervical disc herniation.

What are the important joints in the cervical spine?

The cervical spine contains several types of joints that work together to enable movement of the head and neck. The facet joints guide movement, while the unco-vertebral joints (Luschka's joints) control lateral movement.

How do facet joints guide neck movements?

The facet joints are small joints located at the back of each vertebra. In the upper cervical region, they are oriented horizontally, allowing for more rotation. In the lower cervical region, they become more vertical, guiding flexion and extension.

These joints are covered with cartilage and surrounded by a joint capsule. They can be a source of neck pain, a condition called cervical osteoarthritis. However, as with discs, degenerative changes in these joints are extremely common in people who do not experience any pain.

What are unco-vertebral joints (Luschka's joints)?

The unco-vertebral joints are unique to the cervical region, formed by the unciform processes that rise from the lateral edges of the vertebral bodies C3 to C7. They help stabilize the cervical segments and limit excessive lateral movement.

These joints are not present at birth. They develop gradually during childhood and adolescence as cracks appear in the lateral intervertebral discs. Luschka's joints play a protective role by preventing the disc from protruding laterally toward the nerve roots.

How do the spinal cord and nerves pass through the cervical region?

The spinal cord descends through the spinal canal formed by the stack of vertebrae. Eight pairs of cervical nerves (C1 to C8) emerge from the cervical spine to innervate the arms, hands, and parts of the head and neck.

Why are there eight cervical nerves for seven vertebrae?

Unlike other regions of the spine, the cervical nerves exit ABOVE their corresponding vertebra. The C1 nerve exits above C1, C2 above C2, and so on up to C7. The C8 nerve exits below C7, above T1. This unique numbering system is confusing, but it has important clinical implications.

Which areas of the body does each cervical nerve innervate?

Each cervical nerve root controls specific areas of sensation and movement in the arms and hands. When a nerve is irritated or compressed, symptoms generally follow a predictable pattern.

| Nerve root | Sensitive area | Main muscles | Reflex |

|-----------------|----------------|-------------------|---------|

| C5 | Lateral shoulder, upper arm | Deltoid, biceps | Bicipital |

| C6 | Lateral forearm, thumb, index finger | Biceps, wrist extensors | Brachioradialis |

| C7 | Major (middle finger) | Triceps, wrist flexors | Tricipital |

| C8 | Ring finger, little finger, medial forearm | Finger flexors, interosseous muscles | None |

This information is important for understanding conditions such as cervicobrachialgia or cervical radiculopathy, where pain and symptoms radiate into the arm in a specific pattern.

Which muscles control neck movements?

The cervical muscles are divided into two main groups: the anterior muscles (front of the neck) and the posterior muscles (back of the neck). Together, they enable flexion, extension, rotation, and lateral tilt movements.

What are the anterior neck muscles?

The anterior neck muscles include the deep flexors and superficial muscles such as the sternocleidomastoid. The deep cervical flexors are particularly important for neck stability and postural control.

• Longus colli: Extends from C1 to T3, flexes the neck
• Longus capitis: Flexes the head on the neck
• Rectus capitis anterior: Flexes the head at the atlanto-occipital joint

These deep muscles act as stabilizers. Their weakness has been linked to chronic neck pain in some studies. Physical therapy for neck pain often includes exercises to strengthen these deep stabilizing muscles.

It is the most visible muscle in the neck, forming an oblique band on each side. It attaches to the sternum and clavicle at the bottom, and to the mastoid process of the skull at the top. When it contracts on one side, it turns the head to the opposite side and tilts it to the same side. Tension in the SCM can cause torticollis.

These three muscles (anterior, middle, posterior) attach to the cervical vertebrae and the first two ribs. They participate in lateral flexion of the neck and can also assist in breathing by raising the ribs.

What are the posterior neck muscles?

The posterior neck muscles are organized in layers, from the most superficial to the deepest. They enable extension, rotation, and lateral flexion of the head and neck.

This large diamond-shaped muscle extends from the base of the skull to the middle of the back. Its upper part attaches the cervical vertebrae and skull to the shoulder. It is often tense in people who work hard in front of a screen or suffer from neck pain.

This group of four small deep muscles connects C1 and C2 to the base of the skull:

• Posterior major rectus muscle of the head
• Posterior minor rectus muscle of the head
• Superior oblique muscle of the head
• inferior oblique muscle

These muscles are rich in proprioceptors (position sensors). They play a crucial role in the fine control of head movements and can contribute to headaches of cervical origin (cervicogenic headaches).

These small muscles attach between the vertebrae. They stabilize each vertebral segment individually and contribute to neck extension.

Which ligaments stabilize the cervical spine?

The cervical spine is stabilized by several ligaments that limit excessive movement and protect the nerve structures. Some ligaments are common to the entire spine; others are specific to the upper cervical region.

Which ligaments run through the entire spine?

Extends along the anterior surface of the vertebral bodies, from C1 to the sacrum. It limits excessive extension (bending the head backward).

Extends along the posterior aspect of the vertebral bodies, inside the spinal canal. It limits excessive flexion.

Connects the blades of adjacent vertebrae. Its name comes from its yellowish color due to its high content of elastic fibers.

It is an extension of the supraspinous ligament, specific to the neck. It extends from the external occipital protuberance to C7, attaching to all the cervical spinous processes. It provides an attachment point for several neck muscles.

Which ligaments are specific to C1-C2?

The junction between the skull, C1, and C2 is particularly well stabilized by specialized ligaments because this region allows for a great deal of mobility.

This is the most important ligament for stabilizing the dens of C2. It passes behind the dens, anchoring it against the anterior arch of C1. Rupture of this ligament can lead to severe atlantoaxial instability.

It is the continuation of the posterior longitudinal ligament, which extends to the foramen magnum (the opening in the skull).

These two short but powerful ligaments connect the dens to the occipital condyles. They mainly limit excessive rotation of the head.

How do blood vessels cross the neck?

The vertebral arteries are unique: they pass through the transverse foramina of the C6 to C1 vertebrae before entering the skull to supply the brain. This particular anatomy is an important consideration during certain neck manipulations.

Each vertebral artery follows a characteristic path:

• It originates from the subclavian artery.
• It enters the transverse foramen of C6.
• It ascends through the foramina from C5 to C1.
• It bypasses C1 and enters the skull through the foramen magnum.
• The two vertebral arteries join to form the basilar artery.

These arteries supply approximately 20% of the blood to the brain, primarily feeding the brainstem and cerebellum. Although some have expressed concerns about neck movements and these arteries, studies show that normal head movements do not significantly compromise this blood flow.

What is cervical lordosis and why is it important?

Cervical lordosis is the natural C-shaped curve of the neck, concave toward the back. This curve is not a defect—it is a normal adaptation that helps distribute loads and keep the head balanced on the spine.

Contrary to popular belief, there is no universal "ideal" cervical curvature. Studies show wide variability in normal cervical curvature among people without pain. Some have very curved necks, others almost straight ones—and both can be perfectly normal and functional.

The idea that an "abnormal" curvature causes pain is greatly overestimated. Research has shown that the shape of the cervical curvature does not reliably predict who will experience neck pain. This is reassuring if you have received worrying comments about the shape of your neck.

How can the cervical spine heal and adapt?

Like the rest of your body, the structures of the cervical spine have a remarkable capacity for healing and adaptation. Discs can partially regenerate, muscles can strengthen, and even herniated discs can naturally resolve over time.

This ability to heal is a reason for optimism if you suffer from neck pain. Most neck problems improve with time and proper care. Physical therapy can speed up this process by strengthening stabilizing muscles and improving mobility.

If you experience persistent neck pain or symptoms such as numbness or weakness in your arms, an assessment by a physical therapist can help you identify the source of the problem and develop a personalized treatment plan. Visit our neck pain page to schedule an appointment.